Safety device for excavations



Oct.

Filed O. H. BENINTEND SAFETY DEVICE FOR EXCAVATIONS Nov. 9. 1961 2 Sheets-Sheet 1 mAH/71M Oct- 19, 1955 o. H. BENINTEND SAFETY DEVICE FOR EXCAVATIONS 2 Sheets-Sheet 2 Filed NOV. 9. 1961 /N VE N TOR United States Patent O 3,212,270 SAFETY DEVICE FOR EXCAVATINS Orazio H. Eenintend, Pittsburgh, Pa., assigner to Ben Construction Company, Pittsburgh, Pa., a corporation of Pennsyivania Filed Nov. 9, 1961, Ser. No. 151,259

` 8 Ciaims. (Cl. 6141) :This invention relates to a safety device for excavations to protect laborers and to prevent damage to equipment caused by earth cave-ins or shifting of earth or other material being excavated, and further, to provide guidance to assist in keeping true such an excavation. More particularly, this invention relates to a safety cage to guide movable walls capable of being extended to a selected distance below the cage to provide protection and guidance as aforesaid. Preferably, the cage is demounta-ble and the walls removable therefrom for convenience in transport, or otherwise.

In a safety device of this invention, difiicult soils, sands and/ or other materials can be excavated to predetermined depth manually or using mechanical equipment, without the labor and expense of installing relatively tailor-made boarding and shoring and/or without risking injury to persons in a less protected or unprotected excavation in the course of work thereon and damage to equipment that might be employed in connection therewith. For example, in tie construction of elongated excavations for sewers and utility lines, or of pit excavations for tanks and other underground vessels or equipment, the ground or material in which the excavation is to be made may be relatively subject to slides aud/or collapse whenever the depth of the excavation goes beyond a variable number of -feet depending upon the character of excavation and the ground or material itself. Such problem becomes particularly acute in cases where the depth of tte excavation reaches eight feet or more principally because of possible hazard to personnel working therein. Additionally, an embodiment of this invention enables an excavation to be made which conforms precisely to the engineers drawing location and size including the line of direction and depth of the pipe or other object to be placed in, or uncovered by, such yan excavation operation. Moreover, preferred forms of devices of this invention may be used in end-to-end tandem arrangement for elongated excavation, transported from site to site relatively readily, and, be handled by and utilized with standard excavating operlation machinery.

Other objects, advantages and features of this invention will be apparent from the following description and the accompanying drawings, which are illustrative only, in which FIGURE 1 is a plan view of one preferred embodiment of this invention;

FIGURE 2 is a side View of the embodiment shown in FIGURE l;

FIGURE 3 is an end View of such embodiment illustrating a usage thereof in connection with a trench excavation for pipe;

FIGURE 4 is a view of the upper and lower corners on one side of one end of such device viewed in the direction of arrow 1V marked on FIGURE l to illustrate details of the construction of such corners;

FIGURE 5 is a view of the same corners viewed in the direction of the arrow V marked on FIGURE l;

FIGURE 6 is a view of the upper and lower ends of -a middle post construction shown on such device to show details thereof when viewed in the direction of arrow VI marked on FIGURE l;

3,212,270 Patented ct. 19, 1965 ICC FIGURE 7 is ya detail View of the joint between an upper rail and middle post on one side taken generally along line VII-VII of FIGURE l;

FIGURE 8 is a detail view of a strut adapted to cooperate with holders provided therefor on the middle posts of the illustrated embodiment; and

:FIGURE 9 is a detail view of the intersection of a cross angle brace used at the respective ends of the illustrated embodiment.

Referring to the drawings, there is shown therein a safety device 10 of this invention comprising a cage 11 which preferably is demountable so that 'it may be transported in partially knocked-down condition, and, plates 12 to cooperate with cage 11 by `acting as wall shields for the sides of an excavation 13 inasmuch as the plates 12 are adapted to be progressively lowered as a general rule as the digging of excavation 13 proceeds. Moreover, inasmuch v`as cage '11 may be set in place so as to be both plumb and square, the descent of the side walls '12 in the making of trench excavation 13 will be true for the ascertainment of the engineers objective line 14 representing the axis in the case of a pipe 15, vfor example, t-o be laid in trench 13 with the proper directional orientation, slope (if any), and distance below the top of the ground or other grade. As shown, pipe 15 represents a cross section of a preformed concrete sewer pipe which usually is provided in standard lengths with rone end belled for assembly with an axially adjoining straight end length to provide a continuous line of pipe.

qCage 11 is rectangular in every normal view and cornprises a pair of opposed side panels 16 on opposite sides thereof.1 Each panel 16 has a structural frame comprising vertical end posts 17 rigidly connected to a top rail 18 and a bottom rail 19 Iby welding, bolting, riveting or other secure fastening means. The structural members 17, |18 and 19 are in the form of I or H beams, or other suitable structural element. The vertical posts 17 are deeper to provide inwardly facing opposed anges 20 spaced laterally inwardly `from the inside of the rails 18 and 19. Each post 17 is provided with a filler angle 21 having a flange 22 spaced transversely outwardly of its respective flange 2i), the flange 22 being in the plane of the inside of the respective rails 18 and 19 in the embodiment shown. Each adjacent set of flanges 20 and 22 defines a vertical recess 23 immediately inwardly of the rails 18 and 19 to act as a guiding groove or slideway for the vertical edges of the movable side wall plates 12. Lugs 24 are aflixed to each upper rail 18 of each panel 16 to enable them, or the cage 11 when assembled, to be lifted or otherwise handled by a crane or other lifting equipment using the respective eyes of the lugs 24 when such lifting or other handling is desired. Preferably, the outer side of each panel '16 is closed by a metal sheet 25 which acts as a shutter for the respective sides of cage 11, the sheet-25 being aixed to the frame of such panel `and provided with stitfening ribs 26 aixed to the inside of each respective shutter 25 and the frame.

As illustrated in FIGURES 4 and 5, the upper corners of each panel are each provided with a top bolting plate 27 and a side bolting plate 28, while the lower corners of each panel are each provided with a lower side bolting plate 29. The opposed panels 16 in a cage 11 are spaced a predetermined distance apart Iby cross upper and lower structural members 36' and 31 which may be in the form of angles, or I, or H beams. Such cross members are respectively affixed to straps 32 and 33 respectively drilled for bolts 34 and 35. The bolts 34 and 35 extend through registering bolt openings in the respective bolting plates 27 and 29, and straps 32 and 33, and are held in place by nuts as illustrated, the bolts and nuts being preferably removable when cage 11 is to be transported to avoid damage to such bolts. As shown, the embodiment can be knocked-down for convenience of transport, storage, or other purpose. The respective ends of each cage are symmetrical about a transverse plane through the center, although such is not required and the respective ends may be differently constructed and still be within the purview of this invention.

Each end of cage 11 is also provided in the illustrated embodiment with a cross brace comprising angles 36, one of which is cut out at 37 for the crossover intersection. Further, the respective ends of both angles 36 are cut out at 3S to provide an upper set of overlapping tongues 39 and a lower set of such tongues 40. The upper tongues 39 are bolted to side bolting plates 28 at each side and at each end and the lower tongues 40 are bolted to the lower side bolting plates 29 on each side and at each end. Thus, the cage itself is a rigid unitary cubical structure which can be handled as a unit, when assembled, by the lugs 24 or any of the structural members. Moreover, the width of a cage can be varied at will by changing the respective lengths of the end members accordingly, or having different sets of such end members of different lengths, for such a purpose. Where there is considerable prospective work for a cage of a given excavation size, the cage 11 may be made of a permanently cubical shape by the rigid non-removable atiixation of cross members to the panels.

The embodiment shown illustrates a cage of a double unit length which, for purposes of illustration only, may be taken as having an overall length of feet and an overall width of about 6 feet and an overall height of about 7 feet. The cage is open at the top and the bottom and there is suflicient width in each one-half length thereof for a clam shell bucket, orange peel bucket, or grapple suspended from a crane boom, or the like, to operate to excavate soil or material beneath the bottom of the cage between the sides thereof. In making a trench type excavation, as contrasted with a pit type excavation, a plurality of cages may be utilized in end-to-end relation. In general, the cages act as such a stabilizing force in making an excavation that it is not necessary usually to fasten together the adjoining ends of adjoini-ng cages in longitudinal registry by clamps or otherwise, but such may be done if desired. Further, in smaller lone-unit sizes of cages of this invention, the side panels may have vertical end posts only with upper and lower rails extending therebetween without any utilization of middle posts, to serve the same purposes and achieve the same benefits and advantages of this invention.

In the illustrated embodiment of relatively double length, each panel 16 is provided with a middle post 41 in the .form of an H beam in cross section having op- -positely facing inner flanges 42 and 43 in planar registry with the flanges 20 of the nearer vertical end posts. Additionally, the web of each middle post is provided with ller angles 44 on opposite sides thereof having anges 4S parallel to and laterally outwardly of the respective flanges 42 and 43 to form slideways 46 in backto-back relation facing longitudinally in opposite directions to cooperate respectively with the registering and oppositely facing slideways 23 of the nearer vertical end posts 17 in the same panel 16. Thus, in the embodiment of double unit length, there are four sets of vertical grooves open top and bottom, two sets associated with the inside of each panel to respectively receive the slidable side plates 12 of which there are four in number therein. In a smaller unit 10 with vertical end posts only and no middle posts, there would be only two such wall slidable plates 12, one on each side extendin-g from the groove 23 in one end post 17 to the opposite groove 23 of the other end post 17 on each side 16 of the cage, respectively.

Under some excavation conditions, it may be desirable to laterally support the middle posts on opposite sides of cage 11 against bowing in a horizontal plane and the illustrated embodiment has provision for such additional lateral bracing in the form of a plurality of adjustable jack struts 47. Such strut member may be made in an extensive number of forms including some which may be of a xed length. As shown, strut 47 comprises a pipe body 48 which telescopes freely relative to a jack screw 49 engaged by an abutment nut 5t) having handles 51 to turn the nut so that at least when the ends of the strut are in compression, the length thereof may readily be varied by turning the nut 50. Further, as shown, body 48 is provided with a rectangular pad 52 and screw 49 is provided with another pad 53 at the respective extremities of the strut 47 to tit into notches in bracket holders 54 respectively fastened to the insides of the upper and lower ends of the middle posts 41. Struts 47 may be employed whether or not there are any holders and in some cases no struts will be needed or employed in a practice of this invention.

The slidable wall plates 12 are each preferably of a width which fits freely and slidably in each set of grooves 23-46 on each side of ca-ge 11, the plates having a height two or three or more times greater than the height of cage 11 and panel 16. Preferably, the plates are provided with ears 5S welded thereto for cable or crane hooks or slings to be passed through the eyes thereof to enable each plate to be raised and lowered as, when and to the extent desired. The ears 55 are positioned inwardly of the vertical side edges of the plates 12 so that the top edges of such plates may be lowered to the lower part of the vertical guiding grooves therefor when needed or desired. And, in the lowering of the plates, pneumatic rams or other hammering devices may be applied to the top edges thereof to force them into shielding position along the sides `of an excavation below cage 11, or even into the soil or other material being excavated at the bottom of the excavation if it is so wished as indicated by the dotted lines marked 12a in FIGURE 3. Normally, the bottom edge of the shield plates 12 will be at the bottom of the excavation 13.

For control of holding and/or handling of the plates 12, binding screws 56 preferably are provided extending through holes in the flanges 20, 42 and 43 respectively near the lower ends thereof in the illustrated embodiment. Such binding screws 56 pass freely through such holes in such flanges and are engaged by nuts 57 welded to the respective post at the inner end of such holes facing the inside of cage 11. By means of such binding screws 56, one or more of the plates 12 may selectively be held at a selected elevation in its groove slideways until the time arrives when it is to be moved vertically, at which time the binding screws binding the respective edges oi the plate to be moved are loosened to permit such movement to take place. As an example, if a laborer is working inside of the excavation below plate 12 it may be desirable to bind the plate until he has finished and moved away before it is lowered. When the plates 12 are lowered to an intermedi-ate or full-down position, it is often desirable to use a further series of struts 47 extending across the excavation adjoining each vertical edge of the shield plate 12 for a double length device as illustrated if there is any tendency for the soil on the outside of such plates below cage 11 to slide or shift easily or to tend to flex the lower end of the lowered plates 12 toward the longitudinal center line of the excavation,

In operation, assuming a trench excavation is to be made in troublesome soil 58 beneath a pavement 59, the pavement may be broken manually or by mechanical shovels to make an initial excavation somewhat larger than the size in plan of assembled cage 11. As soon as the excavation has been fairly begun, the cage 11 is set down and carefully plumbed and aligned longitudinally in conformance with engineerings drawings showing the metes and bound of the excavation. Thereafter, manual or mechanical shoveling may take place between the side panels 16, within the ends to each side of the middle posts 41. Such excavation by mechanical shovels with the cage 11 seated leaves a shoulder comparable to the shoulder 60 approximately equal to the width of the panel on each side, which shoulder can easily be removed by workmen who would shovel the soil comprising such shoulder to the center of the cage for removal, after the workmen move away, by the mechanical shovel used to dig further. As the shoulders are cut down, cage 11 will settle, care being taken to insure its continuance in plumb and longitudinally aligned relation to the engineerings drawings until the cage reaches a position approximating that illustrated in FIGURE 3 where it is held by the shoulders 60 during the completion of the excavation. Or, the excavation can be dug to the level of the shoulder 60 before cage 11 is lowered into place and checked for positional conformance to the survey. After the cage is set in place properly plumb, ali-gned and level, soil preferably is backhoed against the outside of the side shutters 25 to hold cage 11 securely in its correctly oriented and operative position relative to the remaining portion of the excavation to be completed therebeneath. Thereafter, as digging proceeds, either manually or by means of a mechanical shovel working in the two halves of the cage 11 illustrated below the bottom thereof, the plates 12 are lowered vertically by slings or otherwise as preferred in correspondence with the increasing depth of the excavation. As digging proceeds, care is taken to see that the plates 12 come down vertically to preserve the alignment wit-h the axis along which the pipe 15 is to be laid, appropriate cross bracing struts 47 being applied, as desired or required, as the excavation deepens beneath the opening of cage 11, usually along the side edges at the ends of the plates and in the center substantially below the struts 47 in holders S4. Thus, excavations can be made relatively quickly, precisely and safely pursuant to this invention.

Upon completion of the excavation covered by cage 11 and after the pipe 15 has been laid and the joints completed and the job inspected and checked, the lower struts 47 are removed and shields 12 are raised by pulling up on the ears 55 thereof as the excavation is back-filled up to the bottom of the cage. Then, such plates 12 are lifted out of the vertical -grooves of cage 11 and put to one side, while the cage 11 is removed readying the whole safety device 10 for use elsewhere farther along in the same excavation, while the space formerly occupied by the cage is filled in completing that section of the excavation.

Various changes may be made in details of the illustrated embodiment and other embodiments provided, as well as other modes and types of use utilized without departing from the spirit of this invention, or the scope of the appended claims.

l claim:

1. A safety device for excavations comprising, in cornbination, a pair of laterally opposed rectangular side panels each having opposite ends and a structural frame therebetween, each frame having horizontal top and bottom rails and vertical end posts rigidly fastened together, said posts at one end having -a flange extending in the direction of the opposite end spaced laterally inwardly of said top and bottom rails, a further flange positioned in parallel adjacency to said first-named flange and substantially in vertical alignment with the inner side of said rails to define a vertical -groove at each end in longitudinal alignment with and facing toward each other, said grooves being open through the top and bottom ends thereof, a slidably removable wall plate for each panel, said longitudinally aligned opposed facing grooves in each panel being adapted to slidably receive said wall plate, and upper and lower cross `members rigidly and respectively connecting corresponding ones of said opposite ends of said panels to form a rigid vertically open cubical cage, whereby a plumbed, -aligned excavation can be dug relatively quickly and safely, said wall plates being insertable and lowerable through said grooves when said cage is in place below the same to act as shields for the sides of said excavation below said cage.

2. A safety device as set forth in claim 1 in which, binding screws are provided extending through the firstnamed flanges of said posts toward said second-named flanges respectively and adapted to engage and hold the side edges of said wall plates respectively at -at least one selected height and means are provided for raising and lowering said cage and wall plates respectively to handle them in the course of excavation operations.

3. A safety device as set forth in claim 2 in which, said last-named means respectively are lugs welded to the upper portion of said frames and inwardly projecting ears welded to the upper portion of said plates longitudinally spaced from said grooves.

4. A safety device as set forth in claim 1 in which, the ends of said panels are provided with bolting plates having a bolt hole therethrough, said cross members are horizontal structural members having straps to overlap said bolting plates respectively, said straps having bolt holes therein to register with said bolt holes in said bolting plates respectively for rigid fastening when said cage is assembled and a cross brace for each end of said cage having diagonal members which are removably secured to said ends respectively.

5. A safety device as set forth in claim 1 in which, a filler member is provided for each of said posts between said rails, each said filler member having said secondnamed flange spaced laterally outwardly of said firstnamed flanges respectively and substantially in the plane of the insides of said rails to provide a continuous groove at each end from top to bottom on each side.

6. In a safety device cage Ifor excavations comprising, in combination, a pair of opposed side panels each having a structural frame, each said frame having horizontal top and bottom rails and vertical end posts rigidly fastened together, said vertical end posts at each end having a flange extending in the direction of the opposite end and adjacent but spaced laterally inwardly of said top and bottom rails to define with said rails in each frame vertical end grooves in longitudinal alignment facing longitudinally toward the center and open top and bottom, a middle post in said frame having a pair of flanges facing the respective ends and spaced inwardly of said rails to define a pair of back-to-back intermediate grooves in longitudinal alignment with the end grooves and facing longitudinally in opposite directions toward the nearer of said end grooves respectively on each side, said intermediate grooves being open top and bottom, planar wall plates having a height greater than the height of said frame, each pair of longitudinally aligned facing grooves on each side being adapted to removably receive and slidably guide one of said planar wall plates, means for rigidly cross connecting the ends of said panels to form a rigid cubical cage open vertically between the sides thereof and at least between said ends and said middles posts respectviely, and a shutter covering the outer side of each of said frames outwardly of said grooves.

7. A safety device as set forth in claim 6 in which, binding screws are provided extending through the respective inner flanges defining the inside of said respective grooves, lifting means are provided on each of said wall plates spaced from the respective pairs of grooves to guide said respective wall plates, removable strut means are provided to extend transversely across said excavation below said cage when said wall plates are therebelow to resist lateral pressure against the outside of said wall plates.

S. A safety device as set forth in claim 6 in which, strut holders are provided on the inside of the upper and lower ends of said middle posts in opposed relation across the width of said cage, adjustable length struts are pro- 7 8 vided which are adapted to be held in said holders to x 2,656,800 10/53 Reising 61--72.1 the minimum distance between said middle posts. 2,777,294 1/ 57 Rosa et al 61-41 2,865,178 12/58 Wieke 61-41 Refexrences Cited by the Examiner 3,016,714 1/62 Cote 61-41 UNITED STATES PATENTS 5 FOREIGN PATENTS 1,161,997 11/15 Thompson 61-28 342,739 1/60 Switzerland. 1,361,516 12/20 Brenton 61-39.1 1,794,704 3 /31 Miller 61 41 EARL J. WITMER, Primary Examiner. 1,935,704 11/ 33 Field 10 JACOB SHAPIRO, WILLIAM I. MUSHAKE, 2,633,713 4/53 Shields 61--41 Examiners. 

1. A SAFETY DEVICES FOR EXCAVATIONS COMPRISING, IN COMBINATION, A PAIR OF LATERALLY OPPOSED RECTANGULAR SIDE PANELS EACH HAVING OPPOSITE ENDS AND A STRUCTURAL FRAME THEREBETWEEN, EACH FRAME HAVING HORIZONTAL TOP AND BOTTOM RAILS AND VERTICAL END POSTS RIGIDLY FASTENDED TOGETHER, SAID POSTS AT ONE END HAVING A FLANGE EXTENDING IN THE DIRECTION OF THE OPPOSITE END SPACED LATERALLY INWARDLY OF SAID TOP AND BOTTOM RAILS, A FURTHER FLANGE POSITIONED IN PARALLEL ADJACENCY TO SAID FIRST-NAMED FLANGE AND SUBSTANTIALLY IN VERTICAL ALIGNMENT WITH THE INNER SIDE OF SAID RAILS TO DEFINE A VERTICAL GROOVE AT EACH END IN LONGITUDINAL ALIGNMENT WITH AND FACING TOWARD EACH OTHER, SAID GROOVES BEING OPEN THROUGH THE TOP AND BOTTOM ENDS THEREOF, A SLIDABLY REMOVABLE WALL PLATE FOR EACH PANEL, SAID LONGITUDINALLY ALIGNED OPPOSED FACING GROOVES IN EACH PANEL BEING ADAPTED TO SLIDABLY RECEIVE SAID WALL PLATE, AND UPPER AND LOWER CROSS MEMBERS RIGIDLY AND RESPECTIVELY CONNECTING CORRESPONDING ONES OF SAID OPPOSITE ENDS OF SAID PANELS TO FORM A RIGID VERTICALLY OPEN CUBICAL CAGE, WHEREBY A PLUMBED, ALIGNED EXCAVATION CAN BE DUG RELATIVELY QUICKLY AND SAFELY, SAID WALL PLATES BEIN INSERTABLE AND LOWERABLE THROUGH SAID GROOVES WHEN SAID CAGE IS IN PLACE BELOW THE SAME TO ACT AS SHIELDS FOR THE SIDES OF SAID EXCAVATION BELOW SAID CAGE. 